1. Field of the Invention
The present invention relates to x-ray film packets, and in particular, to an intra-oral radiographic x-ray film packet which does not employ lead for scattered radiation shielding.
2. Description of the Prior Art
Intra-oral radiographic x-ray film packets, also generally referred to as intra-oral radiographic film packets, or dental x-ray packets, have been employed in dental offices to capture x-rays of a patient's teeth and gums. It is known in the art that heavy metals provide a shielding effect against various forms of radiation. Their effectiveness is associated with the size of their atomic nucleus, or as is commonly referred to in the art, their absorption cross section. An effective heavy metal used to provide the shielding function in current medical and dental radiography is lead (Pb). Lead has several advantages. The ease of which it is formed, combined with its high density and relatively low cost make it a prime material to use in x-ray applications. Lead also provides high quality radiographic images by minimizing the image effects of back scattered radiation.
In utilization of lead (Pb) foil material as the physical state of shielding, an impression in the foil material can be included to visually indicate the orientation of the intra-oral film packet as it was x-ray exposed. The result is a faint image in the processed film chip whereby it alerts the dental practitioner that the film has been oriented in reverse. In conjunction with the functional embodiment of the backscatter inhibiting film packet, lays an interim paper component wrapping the film chip for easy removal of the film chip from the outer envelope, as well as, a barrier against various foreign contamination to the image surface of the film chip, including but not limited to; moisture, oils, scratches, pressure marks.
Finally, the current art embodiment with lead (Pb) shielding includes a position indicating dot (dimple). This indicator is a useful orientation aid for the dental practitioner insomuch that it clearly identifies exposed side, shielded side, top and bottom of the film chip for diagnosis purposes. Although in principle it is not a requirement to have, because without it a trained individual can decipher the chemically processed image and know the orientation it went through at the exposure state. It is fundamentally non-essential for the current state of the art, but does offer a welcome aid to those performing the dental procedures.
The main problem with the current dental intra-oral x-ray film embodiment is the lead (Pb) foil material. Due to imposing regulatory directives regarding hazardous materials, known ramifications of routine contact, and tighter disposal restrictions, lead (Pb) material has become a difficult material to work with, and discard. Although the embodiment requires a backscatter inhibiting feature, lead foil needs to be supplanted for a non-hazardous shielding material of equivalent backscatter protection.
Concerns for environmental issues and environmental consciousness has lead to a perception that heavy metals pose environmental issues in their use, even, in x-ray film packets where the patient has no contact with the lead radiation shield. Still further, there is a desire to eliminate the lead shielding in the x-ray packets, which would normally be discarded after use, and again poses a perception of environmental concern.
U.S. Pat. No. 6,459,091 to DeMeo, relates to a radiation protective garment having barium sulfate coated fibers. U.S. Pat. No. 4,670,658 to Myers is directed to a flexible sheet coated with barium sulfate that is used to shield and protect medical personnel during procedures where radiation back scatter can be a problem. While these systems have achieved a certain degree of success from their particular application, these materials are not suitable for shielding radiation in a dental x-ray packet because of the required thickness needed to provide the equivalent absorption which would make the dental packet exceed the industries standards and norms.
U.S. Pat. No. 6,042,267 to Muraki discloses an intra-oral x-ray image pick up apparatus which uses copper tungsten as an x-ray shielding member, which again is not practical because of the necessary thickness required. Therefore there has been a need to provide a substitute shielding element for the lead commonly used in x-ray film packets which is usually present in the form of a lead strip or film juxtaposed the actual film chip within the packet envelope. Applicant has developed an x-ray film packet in which the shielding member, i.e. the substitute for the lead film, is incorporated directly into the envelope itself and obviates the need for a film insert within the envelope to act as a shielding member.